2023/07/15 by Vinay Sharma, Sharma, Vinay, Rajeev Nepal +3
Physics and Astronomy · #Advanced Condensed Matter Physics #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2307.07795
openalex publication_date 2023/07/15 · openalex created_date 2023/07/20 · openalex updated_date 2026/07/28
Antiferromagnetic Weyl semimetals with spin chirality offer excellent platforms to address the Berry phase physics, which manifests prominently in several of their electro-optical and electro-magnetic responses including as a large anomalous Hall effect (AHE) and spin Hall conductivity. Here, we report measurements of magneto-transport in c-axis textured Mn3Sn thin films grown on the [111] plane of single crystal MgO. At room temperature, these films display a weak uncompensated magnetic moment of ≈ 0.12 \microB/f.u. in the basal plane and a longitudinal resistivity (ρxx) close to ≈ 3.8 \microΩ.m. A residual resistivity ration (ρxx (300 K)/ρxx (2 K)) of ≈ 3.92 further indicates the high quality of the films. While at 300 K a weak AHE together with field-linear Hall resistivity (ρxy) is observed in magnetic fields (H) applied perpendicular to the Kagome planes, the temperature (T) dependence of ρxy shows prominent signatures of three magnetic phases in the temperature regime of 2 to 300 K. The ρxy also derives a non-trivial topological contribution (\rhoTHE ≈ 1nΩ.m) in the spin glass phase which appears at T ≥ 100 K. Our measurements of anisotropic magnetoresistance (AMR) and planar Hall effect (PHE) over a wide H-T phase space reveal the hitherto unseen effects in the three magnetic phases of Mn3Sn. While the AMR and PHE are negative in the inverse triangular spin phase (250 K ≥ T ≥ TN), the helical phase (100 ≥ T ≥ 250 K) is devoid of anisotropic in-plane resistivity, and the spin glass phase shows a sign reversal of AMR with the increasing magnetic field. The origin of this sign change in AMR/PHE is attributed to the emergence of topologically protected spin textures like skyrmions where the fictitious effective magnetic field is estimated to be ≈ 4.4 tesla.